1. Field of the Invention
The present invention relates to an image pick-up device unit having an image pick-up device for obtaining an image signal corresponding to light irradiated on a photoelectrically converting surface or a camera having the image pick-up device unit, such as an interchangeable single-lens reflex digital camera. More particularly, the present invention relates to a camera having a dust-proofing construction of the image pick-up device and image pick-up device unit used for the camera.
2. Description of the Related Art
Recently, digital cameras such as a so-called digital still camera or a digital video camera (hereinafter, referred to as a digital camera or simply referred to as a camera) are generally put into practical use and are widely spread. In the digital cameras, a construction is such that a subject image formed based on beams (hereinafter, referred to as subject beams) from a subject, which is transmitted through a photographing optical system (also referred to as a photographing lens), is formed onto a photoelectrically converting surface of a solid image pick-up device such as a CCD (Charge Coupled Device, hereinafter, briefly referred to as an image pick-up device), which is arranged at a predetermined position. Further, an electrical image signal or the like indicating a desired subject image is generated by using the photoelectrically converting operation of the image pick-up device. A signal based on the image signal and the like is outputted to a predetermined display device such as an LCD (Liquid Crystal Display) and an image or the like is displayed. Another construction is such that the image signal or the like generated by the image pick-up device is recorded to a predetermined recording area of a predetermined recording medium as predetermined-format image data. Further, the image data recorded to the recording medium is read and the image data is converted to become an image signal which is optimum for displaying the image data using the display device. Thereafter, an image corresponding thereto is displayed based on the processed image signal.
In general digital cameras have an optical finder device, so that prior to a photographing operation, a desired subject as a photographing target is observed and a photographing range including the subject is set.
In general, a so-called single-lens reflex finder device is used as the optical finder device. In this single-lens reflex finder device, the advancing direction of the subject beams which are transmitted through the photographing optical system is bent by using a reflecting member arranged on the optical axis of the photographing optical system so that a subject image for observation is formed at a predetermined position. On the other hand, upon photographing operation, the reflecting member is evacuated from the optical axis of the photographing optical system, thereby guiding the subject beams onto a light receiving surface, that is, a photoelectrically converting surface and forming the subject image for photographing on the photographically converting surface.
Furthermore, recently, a so-called interchangeable lens digital camera having the single-lens reflex finder device is generally put into practical use. In the interchangeable lens digital camera, the photographing optical system is detachable to a camera main body, and a plurality of types of the photographing optical systems are selectively used in the single-camera main body by arbitrarily detaching and exchanging a desired photographing optical system in accordance with user's desire.
In the above-mentioned interchangeable lens digital camera, dust and the like floating in the air enter the camera main body upon detaching the photographing optical system from the camera main body. Various mechanisms which are mechanically operated such as a shutter and stop mechanisms are arranged in the camera main body and thus, the dust is possibly generated from the various mechanisms during the operation.
Upon detaching the photographing optical system from the camera main body, the light receiving surface (also referred to as the photoelectrically converting surface) of the image pick-up device arranged in the rear of the photographing optical system is exposed in the ambient air of the camera. Therefore, dust and the like are adhered to the photoelectrically converting surface of the image pick-up device due to electrostatic charge action and the like.
Then, for the conventional single-lens reflex digital cameras, for example, Japanese Unexamined Patent Application Publication No. 2000-29132 proposes a technology for suppressing the adhesion of dust and the like to the light receiving surface of the image pick-up device due to the electrostatic charge action.
Means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like to the light receiving surface of the image pick-up device due to the electrostatic charge action by providing a transparent electrode onto the surface of a cover member for covering the light receiving surface of the image pick-up device provided in the camera and by applying to the transparent electrode a DC voltage or an AC voltage with several kHz to 20 kHz.
The means for neutralizing charges generated to the image pick-up device disclosed in the above publication suppresses the adhesion of dust and the like to the light receiving surface of the image pick-up device due to static electricity.
On the other hand, as the image pick-up device in the conventional digital cameras, a packaged image pick-up device (e.g., referred to as a packaged CCD) is widely used. In addition to the above-mentioned image pick-up device, recently, the supply of a so-called bare CCD chip is proposed.
For example, Japanese Unexamined Patent Application Publication No. 9-130654 discloses means for shaking off dust and the like which are adhered to the photoelectrically converting surface by providing a piezoelectric element between the bare chip CCD and a substrate on which the bare chip CCD is placed and by applying a predetermined voltage to the piezoelectric element, by the reason that dust and the like are, with much possibility, adhered onto the photoelectrically converting surface in the bare chip CCD in many cases.
Further, for example, Japanese Unexamined Patent Application Publication No. 2001-298640 proposes means for removing dust and the like adhered to the surface of an optical member such as a low-pass filter arranged in front of the image pick-up device in the conventional interchangeable lens digital cameras.
The camera disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640 comprises a wiper member as means for removing the dust and the like adhered to the surface of the optical member arranged in front of the image pick-up device.
The wiper member grinds the surface of the optical member such as the low-pass filter and moves on the surface, thereby shaking off dust on the surface of the optical member, thus to remove the dust and the like adhered to the surface of the optical member. The dust and the like grinded by the wiper are put into a groove portion of a camera main body, which is formed near the optical member.
However, the means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like by neutralizing charges on the electrostatic charged image pick-up device. Consequently, the means is not optimal as means for removing dust which is adhered or deposited, irrespective of the static electricity, to the photoelectrically converting surface of the image pick-up device.
Moreover, the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 is not the best means for applying to the image pick-up device such as the packaged CCD generally used for the conventional digital cameras because the means is devised in view of the bare chip CCD.
In other words, when the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 is applied to the general packaged CCD or the like, vibrations to the image pick-up device or the package are applied. Thus, dangerously, the vibrating action adversely influences on various mechanisms which are arranged to the image pick-up device and near it, for example, to cause deterioration or errors.
Furthermore, the means disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640 needs a wiper member and a member such as a driving motor for driving the wiper member. The arrangement of the members requires space in the camera. Therefore, there is a problem that the camera itself is increased in size.
In addition, with the means disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640, dust and the like shaken off by the wiper member are put into the groove portion formed near the optical member. Dust and the like which are put into the groove portion flow into the space of the camera main body again and might be adhered to inner members of the camera main body such as a mirror unit, a shutter unit, and a lens unit for distance measurement, or might be adhered to the optical member again.
In this case, dust and the like adhered to the member are photographed as a part of a captured image or cause inconvenience in the operation of the digital camera.
In particular, in the single-lens reflex digital cameras in which the photographing lens is interchangeable, the acquisition of a preferable result (captured image) needs the suppression of the input of dust and the like in the camera main body. Consequently, dust and the like adhered to the optical member provided in the image pick-up device must accurately be removed. However, with the above means disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640, undesirably, removed dust and the like are adhered again.